Mesa Mark 2B rebuild & MK2C+ Upgrade.

I posted this over at SLOCLONE, Thought you guys might find it interesting too...

Using the (just updated, non-coincidentally) SLOCLONE schematic:
http://sites.google.com/site/danoampstuff/mesa/Mesa_MK2C+_SLOCLONE_v2.pdf

Had this one lying around for years (since 2013), bought this MK2B Combo on Ebay as a non working amp for basically nothing, got it home and opened it up and everything (!) was corroded - Hardest hit were the chassis & all the tube sockets. The transformers, boards and everything else seemed OK though, so I thought it might be a good upgrade candidate.

Unfortunately I lost a lot of the 'before' photos, but you get an idea of the original condition:

So I tore everthing out, sanded & repainted the chassis, designed a new board that would slot into place over the existing socket holes - let me tell ya, it's pretty **** tight in there.









I disassembled a lot of the pots & replaced the tapers with new CTS pot tapers, as the pull pots are the same track / terminals as the new CTS pots of the same size - So basically all the pot tracks are new.

Here it is basically finished:















Just need to finish converting the Combo to a headshell.

Awesome love this sort of stuff

Really nice job! Especially on the accurate layout too - if any info I put out there helped produce this even better. Any clips on how it sounds? I'd love to make up an RP10-A or RP11-A board one day using a double sided FR2 laminate with the original trace layout etc since Mesa don't reproduce these anymore. Such a good job though! Awesome work.

Got the guy some new clothes. and chopped the combo in half. looking slick... I'll get some sounds in as soon as I can get to the jam space.

jrb32 said:

Really nice job! Especially on the accurate layout too - if any info I put out there helped produce this even better. Any clips on how it sounds? I'd love to make up an RP10-A or RP11-A board one day using a double sided FR2 laminate with the original trace layout etc since Mesa don't reproduce these anymore. Such a good job though! Awesome work.

Click to expand...

Oh yeah, thanks for the input for sure matey. That schematic(s) you produced is amazing, that was definitely part of the rebuild. Love your work.

**(spoiler alert - Sounds insane BTW)

Excellent work!

Would you by chance be willing to share the PC board files? I have a candidate for a similar upgrade just sitting here.

Very cool. I’m planning to do something similar, just bought a used IIB myself. Going to make the ++ switchable from a mid pull pot, and attenuate the clean signal to get higher headroom with higher gain settings. I will film the process and put it on YouTube and explain a lot of the design decisions if anyone is interested